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Well, with respect, if I was a breeder I would certainly be concerned about, and want to discuss, any reports suggesting different positioning of dogs' heads for MRI scanning may give different results. I would want to know when I'd spent time and effort (and money) having my breeding stock scanned, that I was getting the most accurate result possible, otherwise it wouldn't be much use in any breeding decisions I had to make, would it?

Well, with respect, if I was a breeder I would certainly be concerned about, and want to discuss, any reports suggesting different positioning of dogs' heads for MRI scanning may give different results. I would want to know when I'd spent time and effort (and money) having my breeding stock scanned, that I was getting the most accurate result possible, otherwise it wouldn't be much use in any breeding decisions I had to make, would it?

Or am I missing something here?

Rosemary

Well, yes, actually you are -- I'd say misunderstanding something though, rather then “missing” something – the "accuracy" of the scan, as far as breeders are concerned (as they are primarily scanning to get a grade) has little to do with the question about head positioning (indeed, if breeders wanted the most accurate results, they would choose neurologists with the most up to date scanning machines, who followed the head positioning protocol for consistency of interpretation for the scanning certificates).

So it isn't a matter of anyone spending money and not getting quality results. The very same breeders, many of whom chose to use scanning programs that used older, lower quality MRI machines, or shorter exposure MRIs, would have a more legitimate concern about the quality of their scans on such machines, as they are well aware, because their scans are already considered substandard for the BVA/KC scanning program. This issue of the quality of the scan was actually raised at various times so it isn't as if some of the informed club people were not aware when they made the choice of where to scan, and certainly there were people on the club committee over time who also were aware of this issue and chose not to discuss it at club level, apparently.

Clare Rusbridge actually raised the issue of the quality of scans obtained with certain scanning methods a long time ago, and has a document on this issue for vets on her website. I would think that the issue of the quality of the scan–which could actually make it look as if a syrinx doesn't exist, when one does–is of far greater importance than the issue of head positioning and herniation: http://www.veterinary-neurologist.co...ening_vets.htm

The position of the head only relates to how much herniation Is seen, and the view of the space between the back of the brain (cerebellum) and the brainstem:

Cerebellar herniation and CSF space between the cerebellum and the brainstem were larger in a flexed head position.

.

Herniation is not a consideration for how a dog is graded for breeding purposes or for how it will be graded under the proposed BVA/KC MRI scheme. CM is only noted as being there, or not there, on the certs -- the degree of CM doesn't influence the grades. As far as I understand, it also would have little influence on any decision about whether to do decompression surgery or not. And it certainly would not influence decisions about medications. It is an alternative way of viewing herniation etc., but I think it would be disputable whether one way of looking at things is better or more useful than another. Herniation is not even seen as a major determinant of pain or of the seriousness of this condition–all the studies have so far have indicated the primary determinant of pain is the width of a syrinx and whether it is symmetrical or asymmetrical. (I am not saying it is irrelevant, but it certainly is not as great a concern as whether there's a syrinx or not.)

So basically, this is a huge drama being created to do precisely what it has succeeded in doing for you –totally confused the issues to make it seem as if this is some massive matter for dispute, and as if there is some criticism to be made about particular approaches to scanning, when actually it is a pretty minor consideration and has already been discussed, as far as I understand, in relation to the stalled BVA/KC scanning scheme that the Cavalier club has roadblocked for months.

... Herniation is not a consideration for how a dog is graded for breeding purposes or for how it will be graded under the proposed BVA/KC MRI scheme. CM is only noted as being there, or not there, on the certs -- the degree of CM doesn't influence the grades. As far as I understand, it also would have little influence on any decision about whether to do decompression surgery or not. And it certainly would not influence decisions about medications. ...

This is consistent with how I read the article and my understanding of the grading (or "coding") of MRI scans.

However, the authors recommend:

"Based on these findings it may be appropriate to position patients in a more flexed head position for optimal imaging in order to identify morphologic changes more accurately. This is important to consider for imaging CKCS with CM especially when studying the pathogenesis of CM/SM."

Another topic covered in this article, if only briefly, is this:

"When CSF space between the cerebellum and brainstem was compared in CKCS with and without SM, there was a significant increase in CSF space in CKCS with CM alone compared to those with CM/SM when head position was flexed. In their cine MR imaging study of CSF flow dynamics in CKCS with CM or CM/SM, Cerda-Gonzalez and others (2009a) found that turbulent CSF flow and jets are associated with SM presence and severity and CSF flow velocity at C2/3 is inversely related to the presence of SM. The reduced CSF space in CM/SM dogs reported in this study could explain this jet like CSF flow in dogs with CM/SM compared to those with CM alone."

I wonder if this means that the severity of CM/SM, or even the presence or future presence of SM, could be predicted based upon the measure of cerebrospinal fluid (CSF) space between the cerebellum and the brainstem. If so, this could go a long way to distinguishing whether a CM-only cavalier is either likely or unlikely to develop SM in the future.

This distinction could be a way to fine-tune a breeding protocol, considering that we now know that over half of cavaliers with SM develop it after their 3rd birthday. If we could reliably count on this measurement of CSF space to tell us if a young dog will, or will not, develop SM in the future, then we could more reliably select SM-free breeding stock at a younger age than the present 2.5 years and the 3+ years the researchers may recommend in the future.

"Based on these findings it may be appropriate to position patients in a more flexed head position for optimal imaging in order to identify morphologic changes more accurately. This is important to consider for imaging CKCS with CM especially when studying the pathogenesis of CM/SM."

Yes, I think it is interesting– though as you note, still not at all relevant to how the dogs end up being graded–especially if the authors are not arguing that CM would be entirely missed. And I would certainly say with confidence, the variation that may be found with head positioning would be no different then the variation that you already get between some neurologists for the interpretation of CM–I am absolutely sure some of the people who were told their dogs did not have CM were told this incorrectly, because I have seen myself MRIs that have been interpreted in 2 different ways by 2 different people on this (and I have one myself). And many neurologist do not seem very familiar with CM at all–especially outside of the UK.

Overall, it is important to note that researchers have always recognized that head position (as well as the quality of the MRI itself) could influence what shows on the MRI and to what degree it shows -- as a matter of fact all these considerations are the basis of why the BVA-KC MRI scheme was created! I do understand from discussions in the past, that some neurologists felt there was an increased risk of complications during MRI if a dog's head is flexed too much, which influenced I am sure the initial decision on a standardized head position. And of course, all of this has been part of the discussion for the BVA/KC scheme. But again, the difference in head positioning would have absolutely no relevance for breeders regarding the certificates they get or their 'quality'.

It would be wonderful if MRIing at alternative angles could help produce a technique for estimating the chance that a dog will go on to develop more severe SM!

But really–it is a bit sad overall that all these elements related to MRIs are still to the forefront when the goal is really to be able to understand the genetic likelihood and have such information linked to a DNA test. That way, breeders could end up only having to spend a minimal amount on a DNA test, and also can use the EBV's for breeding information, and would not have to be doing costly scans. And: the kind of information that comes back from the scans of older Cavaliers gives precisely the information researchers need to understand progression!–again, this would be a far more precise tool than trying to guess from images, and certainly, very few pet owners or breeders are going to of CM/SM and to understand its genetic basis, that owners of cavaliers would feel they need to do costly scans to determine when their dog is likely to get SM, and how much it is likely to suffer.

If breeders would support research by scanning their older dogs, scan their dogs generally and submit the scans for research, support an open health scheme like the BVA/KC MRI scheme, and actually do something, they would get the answers they want, faster.

We are all lucky that researchers take any interest at all in this problem in the breed and that an increasing number are adding to the range of studies done. As with any research, a study is added to the mix and may stand or fall depending on further research, analysis, and insight.

Well, yes, actually you are -- I'd say misunderstanding something though, rather then “missing” something
....
So basically, this is a huge drama being created to do precisely what it has succeeded in doing for you –totally confused the issues to make it seem as if this is some massive matter for dispute...

Well, actually, I'm neither misunderstanding or confused by anything other than why such a huge issue is being made here of the fact that breeders on another forum are debating a topic that is of interest and relevance to them. That is why I was asking what I might be missing, as I completely fail to see why they are apparently being damned for doing so. IMO it's surely much more important for the health and welfare of our breed to concentrate on ways of educating those who care s*d all about the health of their dogs, rather than to continually find fault when a few breeders choose to discuss health issues elsewhere - as far as I'm concerned that's focussing on completely the wrong target...